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fpga滤波器实现 [2020/07/22 14:28] zili |
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- | ### FPGA滤波器实现 | ||
- | \\ | ||
- | |||
- | #### FPGA滤波器实施概述 | ||
- | 我协助我的一位研究生进行了一些有关FPGA滤波器实现的定向研究。她的任务是了解并实现FPGA硬件上的几种类型的过滤器。设计的所有滤波器均为15阶滤波器,并使用16位定点数学运算。然后检查了过滤器的性能和资源使用情况。她关于研究的最终演讲可以在下面查看:\\ | ||
- | |||
- | [[https://www.eetree.cn/wiki/_media/filter_implementation_on_a_fpga_board_xueyan_lu_06152017.pdf|FPGA滤波器实现]]\\ | ||
- | |||
- | 研究项目期间创建的Verilog源文件如下。\\ | ||
- | \\ | ||
- | |||
- | #### FIR滤波器 | ||
- | FIR滤波器是四个滤波器中最简单,最快的。它利用了预加器的对称性。而且,使用加法器树来最小化组合路径延迟。\\ | ||
- | {{ ::fir_filter.png |}} | ||
- | |||
- | ##### FIR_Filter.v | ||
- | <code verilog> | ||
- | |||
- | `define FILT_LENGTH 16 | ||
- | |||
- | module FIR_Filter( | ||
- | input clk, | ||
- | input en, | ||
- | input [15:0]din, | ||
- | output [15:0]dout | ||
- | ); | ||
- | |||
- | reg signed [15:0]coeff[`FILT_LENGTH/2-1:0]; //Filter coefficients. | ||
- | reg signed [15:0]delay_line[`FILT_LENGTH-1:0]; //Input delay line. | ||
- | wire [31:0]accum; //Accumulator for output filter calculation. | ||
- | integer i; //Initialization integer. | ||
- | genvar c; //Delay line generation variable. | ||
- | |||
- | reg signed [16:0]preadd_regs[7:0]; //Save calc after preadd. | ||
- | reg signed [31:0]mult_regs[7:0]; //Save calc after multiplication. | ||
- | reg signed [31:0]tree1_regs[3:0]; //Save calc after first layer of adder tree. | ||
- | reg signed [31:0]tree2_regs[1:0]; //Save calc after first layer of adder tree. | ||
- | reg signed [31:0]treeout_reg; //Save calc after complete. | ||
- | |||
- | //assign dout = treeout_reg[31:16]; | ||
- | | ||
- | //Calculate value in the accumulator. | ||
- | assign accum = (delay_line[0] + delay_line[15]) * coeff[0] + | ||
- | (delay_line[1] + delay_line[14]) * coeff[1] + | ||
- | (delay_line[2] + delay_line[13]) * coeff[2] + | ||
- | (delay_line[3] + delay_line[12]) * coeff[3] + | ||
- | (delay_line[4] + delay_line[11]) * coeff[4] + | ||
- | (delay_line[5] + delay_line[10]) * coeff[5] + | ||
- | (delay_line[6] + delay_line[9]) * coeff[6] + | ||
- | (delay_line[7] + delay_line[8]) * coeff[7]; | ||
- | |||
- | //Assign upper 16-bits to output. | ||
- | assign dout = accum[31:16]; | ||
- | | ||
- | initial begin | ||
- | //Load the filter coefficients. | ||
- | coeff[0] = 16'd2320; | ||
- | coeff[1] = 16'd4143; | ||
- | coeff[2] = 16'd4592; | ||
- | coeff[3] = 16'd7278; | ||
- | coeff[4] = 16'd8423; | ||
- | coeff[5] = 16'd10389; | ||
- | coeff[6] = 16'd11269; | ||
- | coeff[7] = 16'd12000; | ||
- | |||
- | //Initialize delay line. | ||
- | for(i = 0; i < `FILT_LENGTH; i = i+1'b1) begin | ||
- | delay_line[i] = 16'd0; | ||
- | end | ||
- | | ||
- | //Initialize the preadder regs. | ||
- | for(i = 0; i < 8; i = i+1'b1) begin | ||
- | preadd_regs[i] = 17'd0; | ||
- | end | ||
- | | ||
- | //Initialize the multiplier regs. | ||
- | for(i = 0; i < 8; i = i+1'b1) begin | ||
- | mult_regs[i] = 32'd0; | ||
- | end | ||
- | | ||
- | //Initialize the first layer of the adder tree regs. | ||
- | for(i = 0; i < 4; i = i+1'b1) begin | ||
- | tree1_regs[i] = 32'd0; | ||
- | end | ||
- | | ||
- | //Initialize the second layer of the adder tree regs. | ||
- | for(i = 0; i < 2; i = i+1'b1) begin | ||
- | tree2_regs[i] = 32'd0; | ||
- | end | ||
- | | ||
- | //Initialize the adder tree output reg. | ||
- | treeout_reg = 32'd0; | ||
- | end | ||
- | | ||
- | //Advance the data through the delay line every clock cycle. | ||
- | generate | ||
- | for (c = `FILT_LENGTH-1; c > 0; c = c - 1) begin: inc_delay | ||
- | always @(posedge clk) begin | ||
- | if(en) delay_line[c] <= delay_line[c-1]; | ||
- | end | ||
- | end | ||
- | endgenerate | ||
- | | ||
- | //Update with input data. | ||
- | always @(posedge clk) begin | ||
- | if(en) delay_line[0] <= din; | ||
- | end | ||
- | endmodule | ||
- | |||
- | </code> | ||
- | \\ | ||
- | |||
- | ##### filter_top.v | ||
- | <code verilog> | ||
- | |||
- | module filter_top( | ||
- | input clk, | ||
- | input [7:0]sw, | ||
- | output [7:0]JA | ||
- | ); | ||
- | | ||
- | wire [15:0]tout; //The output of the tone lookup table. | ||
- | wire [15:0]fout; //The output of the FIR filter. | ||
- | wire [15:0]mout; //Selected output. | ||
- | wire en; //Clock enble. | ||
- | wire clk_out; //264MHz System clock. | ||
- | | ||
- | assign en = 1'b1; | ||
- | | ||
- | clk_wiz_0 cw (.clk_in1(clk), .clk_out1(clk_out)); | ||
- | //clk_en ce(.clk(clk_out), .en(en)); | ||
- | ToneGen tg(.clk(clk_out), .en(en), .dout(tout)); | ||
- | FIR_Filter ff(.clk(clk_out), .en(en), .din(tout), .dout(fout)); | ||
- | | ||
- | //Choose filtered or unfiltered output based on sw0. | ||
- | assign mout = sw[0] ? fout : tout; | ||
- | | ||
- | //Take only the upper 8 bits and make it unsigned. | ||
- | //assign JA = mout[15:8] + 8'd128; | ||
- | assign {JA[3:0], JA[7:4]} = mout[15:8] + 8'd128; | ||
- | | ||
- | endmodule | ||
- | |||
- | </code> | ||
- | \\ | ||
- | |||
- | ##### ToneGen.v | ||
- | <code verilog> | ||
- | |||
- | `timescale 1ns/1ps | ||
- | |||
- | module ToneGen( | ||
- | input clk, | ||
- | input en, | ||
- | output [15:0]dout | ||
- | ); | ||
- | |||
- | //Tone generation data. At a 44KHz sampling rate, the lookup table | ||
- | //generates a 440Hz and 4.4KHz tone mixed together. | ||
- | reg [15:0]tonetbl[99:0]; | ||
- | | ||
- | //Pointer into the tone table. | ||
- | reg [6:0]toneptr = 7'h00; | ||
- | | ||
- | initial begin | ||
- | tonetbl[0] = 10970; | ||
- | tonetbl[1] = 18151; | ||
- | tonetbl[2] = 19197; | ||
- | tonetbl[3] = 14105; | ||
- | tonetbl[4] = 5211; | ||
- | tonetbl[5] = -3704; | ||
- | tonetbl[6] = -8858; | ||
- | tonetbl[7] = -7914; | ||
- | tonetbl[8] = -876; | ||
- | tonetbl[9] = 9912; | ||
- | tonetbl[10] = 20660; | ||
- | tonetbl[11] = 27581; | ||
- | tonetbl[12] = 28330; | ||
- | tonetbl[13] = 22905; | ||
- | tonetbl[14] = 13642; | ||
- | tonetbl[15] = 4326; | ||
- | tonetbl[16] = -1260; | ||
- | tonetbl[17] = -780; | ||
- | tonetbl[18] = 5767; | ||
- | tonetbl[19] = 16037; | ||
- | tonetbl[20] = 26244; | ||
- | tonetbl[21] = 32601; | ||
- | tonetbl[22] = 32767; | ||
- | tonetbl[23] = 26741; | ||
- | tonetbl[24] = 16863; | ||
- | tonetbl[25] = 6918; | ||
- | tonetbl[26] = 692; | ||
- | tonetbl[27] = 527; | ||
- | tonetbl[28] = 6421; | ||
- | tonetbl[29] = 16037; | ||
- | tonetbl[30] = 25590; | ||
- | tonetbl[31] = 31295; | ||
- | tonetbl[32] = 30814; | ||
- | tonetbl[33] = 24149; | ||
- | tonetbl[34] = 13642; | ||
- | tonetbl[35] = 3081; | ||
- | tonetbl[36] = -3745; | ||
- | tonetbl[37] = -4494; | ||
- | tonetbl[38] = 837; | ||
- | tonetbl[39] = 9912; | ||
- | tonetbl[40] = 18947; | ||
- | tonetbl[41] = 24161; | ||
- | tonetbl[42] = 23217; | ||
- | tonetbl[43] = 16119; | ||
- | tonetbl[44] = 5211; | ||
- | tonetbl[45] = -5718; | ||
- | tonetbl[46] = -12878; | ||
- | tonetbl[47] = -13924; | ||
- | tonetbl[48] = -8853; | ||
- | tonetbl[49] = 0; | ||
- | tonetbl[50] = 8853; | ||
- | tonetbl[51] = 13924; | ||
- | tonetbl[52] = 12878; | ||
- | tonetbl[53] = 5718; | ||
- | tonetbl[54] = -5211; | ||
- | tonetbl[55] = -16119; | ||
- | tonetbl[56] = -23217; | ||
- | tonetbl[57] = -24161; | ||
- | tonetbl[58] = -18947; | ||
- | tonetbl[59] = -9912; | ||
- | tonetbl[60] = -837; | ||
- | tonetbl[61] = 4494; | ||
- | tonetbl[62] = 3745; | ||
- | tonetbl[63] = -3081; | ||
- | tonetbl[64] = -13642; | ||
- | tonetbl[65] = -24149; | ||
- | tonetbl[66] = -30814; | ||
- | tonetbl[67] = -31295; | ||
- | tonetbl[68] = -25590; | ||
- | tonetbl[69] = -16037; | ||
- | tonetbl[70] = -6421; | ||
- | tonetbl[71] = -527; | ||
- | tonetbl[72] = -692; | ||
- | tonetbl[73] = -6918; | ||
- | tonetbl[74] = -16863; | ||
- | tonetbl[75] = -26741; | ||
- | tonetbl[76] = -32767; | ||
- | tonetbl[77] = -32601; | ||
- | tonetbl[78] = -26244; | ||
- | tonetbl[79] = -16037; | ||
- | tonetbl[80] = -5767; | ||
- | tonetbl[81] = 780; | ||
- | tonetbl[82] = 1260; | ||
- | tonetbl[83] = -4326; | ||
- | tonetbl[84] = -13642; | ||
- | tonetbl[85] = -22905; | ||
- | tonetbl[86] = -28330; | ||
- | tonetbl[87] = -27581; | ||
- | tonetbl[88] = -20660; | ||
- | tonetbl[89] = -9912; | ||
- | tonetbl[90] = 876; | ||
- | tonetbl[91] = 7914; | ||
- | tonetbl[92] = 8858; | ||
- | tonetbl[93] = 3704; | ||
- | tonetbl[94] = -5211; | ||
- | tonetbl[95] = -14105; | ||
- | tonetbl[96] = -19197; | ||
- | tonetbl[97] = -18151; | ||
- | tonetbl[98] = -10970; | ||
- | tonetbl[99] = 0; | ||
- | end | ||
- | |||
- | //Assign the output to the value in the lookup table | ||
- | //pointed to by toneptr. | ||
- | assign dout = tonetbl[toneptr]; | ||
- | |||
- | //Increment through the tone lookup table and wrap back | ||
- | //to zero when at the end. | ||
- | always @(posedge clk) begin | ||
- | if(en) begin | ||
- | if(toneptr == 7'd99) begin | ||
- | toneptr <= 7'd0; | ||
- | end | ||
- | else begin | ||
- | toneptr <= toneptr + 1'b1; | ||
- | end | ||
- | end | ||
- | end | ||
- | endmodule | ||
- | |||
- | </code> | ||
- | \\ | ||
- | |||
- | |||
- | ##### clk_en.v | ||
- | <code verilog> | ||
- | |||
- | module clk_en( | ||
- | input clk, | ||
- | output reg en = 1'b0 | ||
- | ); | ||
- | |||
- | reg [15:0]en_counter = 16'h0; | ||
- | | ||
- | always @(posedge clk) begin | ||
- | if(en_counter == 16'd5999) begin | ||
- | en_counter <= 16'h0; | ||
- | en <= 1'b1; | ||
- | end | ||
- | else begin | ||
- | en_counter <= en_counter + 1'b1; | ||
- | en <= 1'b0; | ||
- | end | ||
- | end | ||
- | |||
- | endmodule | ||
- | |||
- | </code> | ||
- | \\ | ||
- | |||
- | ##### TB_ToneGen.v | ||
- | <code verilog> | ||
- | |||
- | module TB_ToneGen; | ||
- | |||
- | reg clk = 1'b0; | ||
- | reg sw0 = 1'b1; | ||
- | wire [7:0]JA; | ||
- | | ||
- | wire en; | ||
- | //wire [15:0]cout; | ||
- | | ||
- | filter_top uut(.clk(clk), .sw({15'h00,sw0}), .JA({JA[3:0], JA[7:4]})); | ||
- | | ||
- | assign en = uut.en; | ||
- | //assign cout = uut.ce.en_counter; | ||
- | | ||
- | //initial begin | ||
- | // #600000 sw0 = 1'b1; | ||
- | //end | ||
- | | ||
- | //100MHz clock | ||
- | always #5 clk = ~clk; | ||
- | endmodule | ||
- | |||
- | </code> | ||
- | \\ | ||
- | |||
- | \\ | ||
- | #### LMS自适应滤波器 | ||
- | LMS自适应滤波器在单个时钟周期内完成其输出计算和权重更新。由于其单周期运行,因此存在大量的组合延迟。该滤波器只能以FIR滤波器速度的一小部分运行。\\ | ||
- | {{ ::lms_adaptive_filter.png |}} | ||
- | |||
- | ##### LMS_Adapt.v | ||
- | <code verilog> | ||
- | |||
- | `define ADAPT_FILT_LENGTH 16 | ||
- | module LMS_Adapt( | ||
- | input clk, | ||
- | input en, | ||
- | input [15:0]din, | ||
- | input signed [15:0]desired, | ||
- | output signed [15:0]dout, | ||
- | output signed [15:0]err | ||
- | ); | ||
- | |||
- | parameter MU = 16'd32767; | ||
- | | ||
- | reg signed [15:0]mu = MU; | ||
- | reg signed [15:0]coeff[`ADAPT_FILT_LENGTH-1:0]; //Filter coefficients. | ||
- | reg signed [15:0]delay_line[`ADAPT_FILT_LENGTH-1:0]; //Input delay line. | ||
- | wire signed [31:0]accum; //Accumulator for output filter calculation. | ||
- | wire signed [31:0]stepped; //Error after step sized applied. | ||
- | integer i; //Initialization integer. | ||
- | genvar c; //Delay line generation variable. | ||
- | | ||
- | //Calculate the error and multiply it by the step size. | ||
- | assign err = desired - dout; | ||
- | //assign stepped = err * mu; | ||
- | assign stepped = err << 15; | ||
- | | ||
- | //Calculate value in the accumulator. | ||
- | assign accum = delay_line[0]*coeff[0] + | ||
- | delay_line[1]*coeff[1] + | ||
- | delay_line[2]*coeff[2] + | ||
- | delay_line[3]*coeff[3] + | ||
- | delay_line[4]*coeff[4] + | ||
- | delay_line[5]*coeff[5] + | ||
- | delay_line[6]*coeff[6] + | ||
- | delay_line[7]*coeff[7] + | ||
- | delay_line[8]*coeff[8] + | ||
- | delay_line[9]*coeff[9] + | ||
- | delay_line[10]*coeff[10] + | ||
- | delay_line[11]*coeff[11] + | ||
- | delay_line[12]*coeff[12] + | ||
- | delay_line[13]*coeff[13] + | ||
- | delay_line[14]*coeff[14] + | ||
- | delay_line[15]*coeff[15]; | ||
- | |||
- | //Assign upper 16-bits to output. | ||
- | assign dout = accum[31:16]; | ||
- | |||
- | initial begin | ||
- | //Load the filter coefficients. | ||
- | coeff[0] = 20'd0; | ||
- | coeff[1] = 20'd0; | ||
- | coeff[2] = 20'd0; | ||
- | coeff[3] = 20'd0; | ||
- | coeff[4] = 20'd0; | ||
- | coeff[5] = 20'd0; | ||
- | coeff[6] = 20'd0; | ||
- | coeff[7] = 20'd0; | ||
- | coeff[8] = 20'd0; | ||
- | coeff[9] = 20'd0; | ||
- | coeff[10] = 20'd0; | ||
- | coeff[11] = 20'd0; | ||
- | coeff[12] = 20'd0; | ||
- | coeff[13] = 20'd0; | ||
- | coeff[14] = 20'd0; | ||
- | coeff[15] = 20'd0; | ||
- | |||
- | //Initialize delay line. | ||
- | for(i = 0; i < `ADAPT_FILT_LENGTH; i = i+1'b1) begin | ||
- | delay_line[i] = 16'd0; | ||
- | end | ||
- | end | ||
- | | ||
- | //Advance the data through the delay line every clock cycle. | ||
- | generate | ||
- | for (c = `ADAPT_FILT_LENGTH-1; c > 0; c = c - 1) begin: inc_delay | ||
- | always @(posedge clk) begin | ||
- | if(en) delay_line[c] <= delay_line[c-1]; | ||
- | end | ||
- | end | ||
- | endgenerate | ||
- | | ||
- | //Update with input data. | ||
- | always @(posedge clk) begin | ||
- | if(en) delay_line[0] <= din; | ||
- | end | ||
- | | ||
- | wire signed [31:0]num2[`ADAPT_FILT_LENGTH-1:0]; | ||
- | wire signed [15:0]n1[`ADAPT_FILT_LENGTH-1:0]; | ||
- | wire signed [15:0]n2[`ADAPT_FILT_LENGTH-1:0]; | ||
- | | ||
- | //Update the coefficients with the LMS algorithm. | ||
- | generate | ||
- | for (c = `ADAPT_FILT_LENGTH; c > 0; c = c - 1) begin: adapt_update | ||
- | assign n1[c-1] = stepped[31:16]; | ||
- | | ||
- | assign num2[c-1] = n1[c-1]*delay_line[c-1]; | ||
- | assign n2[c-1] = num2[c-1][31:16]; | ||
- | | ||
- | always @(posedge clk) begin | ||
- | if(en) coeff[c-1] <= coeff[c-1] + n2[c-1]; | ||
- | end | ||
- | end | ||
- | endgenerate | ||
- | endmodule | ||
- | |||
- | </code> | ||
- | \\ | ||
- | |||
- | ##### filter_top.v | ||
- | <code verilog> | ||
- | |||
- | module filter_top( | ||
- | input clk, | ||
- | input [7:0]sw, | ||
- | output [7:0]JA | ||
- | ); | ||
- | | ||
- | wire signed [15:0]tout; //Output of the tone lookup table. | ||
- | wire [15:0]fout; //Output of the FIR filter. | ||
- | wire [15:0]aout; //Output of the adaptive filter. | ||
- | wire [15:0]err; //Adaptive filter error. | ||
- | wire [15:0]lfsr_out; //16-bit Random noise variable. | ||
- | wire en; //Clock enble. | ||
- | wire [9:0]rnd; //10-bit noise. | ||
- | wire signed [15:0]tone_and_noise; //Combination of tone and noise. | ||
- | wire signed [15:0]delay_out; //Output of the delay line. | ||
- | wire [15:0]mout; //Selected desired output. | ||
- | wire clk19_8MHz; //19.8MHz system clock. | ||
- | |||
- | assign rnd = lfsr_out[15:6]; | ||
- | assign tone_and_noise = tout + rnd; | ||
- | //assign en = 1'b1; | ||
- | | ||
- | clk_wiz_0 cw(.clk_in1(clk), .clk_out1(clk19_8MHz), .reset(1'b0)); | ||
- | ToneGen tg(.clk(clk19_8MHz), .en(en), .dout(tout)); | ||
- | FIR_Filter ff(.clk(clk19_8MHz), .en(en), .din(tone_and_noise), .dout(fout)); | ||
- | LMS_Adapt af(.clk(clk19_8MHz), .en(en), .din(tone_and_noise), .desired(mout), .dout(aout), .err(err)); | ||
- | lfsr sr(.clk(clk19_8MHz), .en(en), .lfsr_out(lfsr_out)); | ||
- | clk_en ce(.clk(clk19_8MHz), .en(en)); | ||
- | | ||
- | //Choose filtered or unfiltered output based on sw0. | ||
- | assign mout = sw[0] ? fout : tone_and_noise;//delay_out; | ||
- | | ||
- | //Take only the upper 8 bits and make it unsigned. | ||
- | assign {JA[3:0], JA[7:4]} = aout[15:8] + 8'd128; | ||
- | //assign JA[7:0] = aout[15:8] + 8'd128; | ||
- | | ||
- | //assign {JA[3:0], JA[7:4]} = sw[7:0]; | ||
- | endmodule | ||
- | |||
- | </code> | ||
- | \\ | ||
- | |||
- | ##### ToneGen.v | ||
- | <code verilog> | ||
- | |||
- | `timescale 1ns/1ps | ||
- | |||
- | module ToneGen( | ||
- | input clk, | ||
- | input en, | ||
- | output [15:0]dout | ||
- | ); | ||
- | |||
- | //Tone generation data. At a 44KHz sampling rate, the lookup table | ||
- | //generates a 440Hz and 4.4KHz tone mixed together. | ||
- | reg [15:0]tonetbl[99:0]; | ||
- | | ||
- | //Pointer into the tone table. | ||
- | reg [6:0]toneptr = 7'h00; | ||
- | | ||
- | initial begin | ||
- | tonetbl[0] = 10970; | ||
- | tonetbl[1] = 18151; | ||
- | tonetbl[2] = 19197; | ||
- | tonetbl[3] = 14105; | ||
- | tonetbl[4] = 5211; | ||
- | tonetbl[5] = -3704; | ||
- | tonetbl[6] = -8858; | ||
- | tonetbl[7] = -7914; | ||
- | tonetbl[8] = -876; | ||
- | tonetbl[9] = 9912; | ||
- | tonetbl[10] = 20660; | ||
- | tonetbl[11] = 27581; | ||
- | tonetbl[12] = 28330; | ||
- | tonetbl[13] = 22905; | ||
- | tonetbl[14] = 13642; | ||
- | tonetbl[15] = 4326; | ||
- | tonetbl[16] = -1260; | ||
- | tonetbl[17] = -780; | ||
- | tonetbl[18] = 5767; | ||
- | tonetbl[19] = 16037; | ||
- | tonetbl[20] = 26244; | ||
- | tonetbl[21] = 32601; | ||
- | tonetbl[22] = 32767; | ||
- | tonetbl[23] = 26741; | ||
- | tonetbl[24] = 16863; | ||
- | tonetbl[25] = 6918; | ||
- | tonetbl[26] = 692; | ||
- | tonetbl[27] = 527; | ||
- | tonetbl[28] = 6421; | ||
- | tonetbl[29] = 16037; | ||
- | tonetbl[30] = 25590; | ||
- | tonetbl[31] = 31295; | ||
- | tonetbl[32] = 30814; | ||
- | tonetbl[33] = 24149; | ||
- | tonetbl[34] = 13642; | ||
- | tonetbl[35] = 3081; | ||
- | tonetbl[36] = -3745; | ||
- | tonetbl[37] = -4494; | ||
- | tonetbl[38] = 837; | ||
- | tonetbl[39] = 9912; | ||
- | tonetbl[40] = 18947; | ||
- | tonetbl[41] = 24161; | ||
- | tonetbl[42] = 23217; | ||
- | tonetbl[43] = 16119; | ||
- | tonetbl[44] = 5211; | ||
- | tonetbl[45] = -5718; | ||
- | tonetbl[46] = -12878; | ||
- | tonetbl[47] = -13924; | ||
- | tonetbl[48] = -8853; | ||
- | tonetbl[49] = 0; | ||
- | tonetbl[50] = 8853; | ||
- | tonetbl[51] = 13924; | ||
- | tonetbl[52] = 12878; | ||
- | tonetbl[53] = 5718; | ||
- | tonetbl[54] = -5211; | ||
- | tonetbl[55] = -16119; | ||
- | tonetbl[56] = -23217; | ||
- | tonetbl[57] = -24161; | ||
- | tonetbl[58] = -18947; | ||
- | tonetbl[59] = -9912; | ||
- | tonetbl[60] = -837; | ||
- | tonetbl[61] = 4494; | ||
- | tonetbl[62] = 3745; | ||
- | tonetbl[63] = -3081; | ||
- | tonetbl[64] = -13642; | ||
- | tonetbl[65] = -24149; | ||
- | tonetbl[66] = -30814; | ||
- | tonetbl[67] = -31295; | ||
- | tonetbl[68] = -25590; | ||
- | tonetbl[69] = -16037; | ||
- | tonetbl[70] = -6421; | ||
- | tonetbl[71] = -527; | ||
- | tonetbl[72] = -692; | ||
- | tonetbl[73] = -6918; | ||
- | tonetbl[74] = -16863; | ||
- | tonetbl[75] = -26741; | ||
- | tonetbl[76] = -32767; | ||
- | tonetbl[77] = -32601; | ||
- | tonetbl[78] = -26244; | ||
- | tonetbl[79] = -16037; | ||
- | tonetbl[80] = -5767; | ||
- | tonetbl[81] = 780; | ||
- | tonetbl[82] = 1260; | ||
- | tonetbl[83] = -4326; | ||
- | tonetbl[84] = -13642; | ||
- | tonetbl[85] = -22905; | ||
- | tonetbl[86] = -28330; | ||
- | tonetbl[87] = -27581; | ||
- | tonetbl[88] = -20660; | ||
- | tonetbl[89] = -9912; | ||
- | tonetbl[90] = 876; | ||
- | tonetbl[91] = 7914; | ||
- | tonetbl[92] = 8858; | ||
- | tonetbl[93] = 3704; | ||
- | tonetbl[94] = -5211; | ||
- | tonetbl[95] = -14105; | ||
- | tonetbl[96] = -19197; | ||
- | tonetbl[97] = -18151; | ||
- | tonetbl[98] = -10970; | ||
- | tonetbl[99] = 0; | ||
- | end | ||
- | |||
- | //Assign the output to the value in the lookup table | ||
- | //pointed to by toneptr. | ||
- | assign dout = tonetbl[toneptr]; | ||
- | |||
- | //Increment through the tone lookup table and wrap back | ||
- | //to zero when at the end. | ||
- | always @(posedge clk) begin | ||
- | if(en) begin | ||
- | if(toneptr == 7'd99) begin | ||
- | toneptr <= 7'd0; | ||
- | end | ||
- | else begin | ||
- | toneptr <= toneptr + 1'b1; | ||
- | end | ||
- | end | ||
- | end | ||
- | endmodule | ||
- | |||
- | </code> | ||
- | \\ | ||
- | |||
- | ##### FIR_Filter.v | ||
- | <code verilog> | ||
- | |||
- | `define FILT_LENGTH 16 | ||
- | |||
- | module FIR_Filter( | ||
- | input clk, | ||
- | input en, | ||
- | input [15:0]din, | ||
- | output [15:0]dout | ||
- | ); | ||
- | |||
- | reg signed [15:0]coeff[`FILT_LENGTH/2-1:0]; //Filter coefficients. | ||
- | reg signed [15:0]delay_line[`FILT_LENGTH-1:0]; //Input delay line. | ||
- | wire [31:0]accum; //Accumulator for output filter calculation. | ||
- | integer i; //Initialization integer. | ||
- | genvar c; //Delay line generation variable. | ||
- | | ||
- | //Calculate value in the accumulator. | ||
- | assign accum = (delay_line[0] + delay_line[15]) * coeff[0] + | ||
- | (delay_line[1] + delay_line[14]) * coeff[1] + | ||
- | (delay_line[2] + delay_line[13]) * coeff[2] + | ||
- | (delay_line[3] + delay_line[12]) * coeff[3] + | ||
- | (delay_line[4] + delay_line[11]) * coeff[4] + | ||
- | (delay_line[5] + delay_line[10]) * coeff[5] + | ||
- | (delay_line[6] + delay_line[9]) * coeff[6] + | ||
- | (delay_line[7] + delay_line[8]) * coeff[7]; | ||
- | |||
- | //Assign upper 16-bits to output. | ||
- | assign dout = accum[31:16]; | ||
- | |||
- | initial begin | ||
- | //Load the filter coefficients. | ||
- | coeff[0] = 16'd2552; | ||
- | coeff[1] = 16'd4557; | ||
- | coeff[2] = 16'd5051; | ||
- | coeff[3] = 16'd8006; | ||
- | coeff[4] = 16'd9265; | ||
- | coeff[5] = 16'd11427; | ||
- | coeff[6] = 16'd12396; | ||
- | coeff[7] = 16'd13200; | ||
- | |||
- | //Initialize delay line. | ||
- | for(i = 0; i < `FILT_LENGTH; i = i+1'b1) begin | ||
- | delay_line[i] = 16'd0; | ||
- | end | ||
- | end | ||
- | | ||
- | //Advance the data through the delay line every clock cycle. | ||
- | generate | ||
- | for (c = `FILT_LENGTH-1; c > 0; c = c - 1) begin: inc_delay | ||
- | always @(posedge clk) begin | ||
- | if(en) delay_line[c] <= delay_line[c-1]; | ||
- | end | ||
- | end | ||
- | endgenerate | ||
- | | ||
- | //Update with input data. | ||
- | always @(posedge clk) begin | ||
- | if(en) delay_line[0] <= din; | ||
- | end | ||
- | endmodule | ||
- | |||
- | </code> | ||
- | \\ | ||
- | |||
- | ##### clk_en.v | ||
- | <code verilog> | ||
- | |||
- | module clk_en( | ||
- | input clk, | ||
- | output reg en = 1'b0 | ||
- | ); | ||
- | |||
- | reg [15:0]en_counter = 16'h0; | ||
- | | ||
- | always @(posedge clk) begin | ||
- | if(en_counter == 16'd449) begin | ||
- | en_counter <= 16'h0; | ||
- | en <= 1'b1; | ||
- | end | ||
- | else begin | ||
- | en_counter <= en_counter + 1'b1; | ||
- | en <= 1'b0; | ||
- | end | ||
- | end | ||
- | |||
- | endmodule | ||
- | |||
- | </code> | ||
- | \\ | ||
- | |||
- | ##### lfsr.v | ||
- | <code verilog> | ||
- | |||
- | `timescale 1ns / 1ps | ||
- | |||
- | module lfsr( | ||
- | input clk, | ||
- | input en, | ||
- | input rst, | ||
- | output [15:0]lfsr_out | ||
- | ); | ||
- | | ||
- | //Create a 16-bit linear feedback shift register with | ||
- | //maximal polynomial x^16 + x^14 + x^13 + x^11 + 1. | ||
- | reg [15:0]lfsr = 16'd1; | ||
- | wire feedback; | ||
- | | ||
- | assign feedback = ((lfsr[15] ^ lfsr[13]) ^ lfsr[12]) ^ lfsr[10]; | ||
- | assign lfsr_out = lfsr; | ||
- | | ||
- | //Update the linear feedback shift register. | ||
- | always @(posedge clk) begin | ||
- | if(rst) lfsr <= 16'd1; | ||
- | else if(en) lfsr <= {lfsr[14:0], feedback}; | ||
- | end | ||
- | endmodule | ||
- | |||
- | </code> | ||
- | \\ | ||
- | |||
- | ##### TB_LMS_Adapt.v | ||
- | <code verilog> | ||
- | |||
- | module TB_LMS_Adapt; | ||
- | |||
- | reg clk = 1'b0; | ||
- | reg [7:0]sw = 1'b1; | ||
- | wire [7:0]JA; | ||
- | | ||
- | wire [15:0]d; | ||
- | wire [15:0]y; | ||
- | wire [15:0]e; | ||
- | wire [15:0]n1; | ||
- | | ||
- | filter_top uut(.clk(clk), .sw(sw), .JA(JA)); | ||
- | | ||
- | assign d = uut.fout; | ||
- | assign y = uut.aout; | ||
- | assign e = uut.err; | ||
- | assign n1 = uut.af.n1[0]; | ||
- | |||
- | always #5 clk = ~clk; | ||
- | | ||
- | initial begin | ||
- | //#20000000 sw[0] = 1'b1; | ||
- | //#40000 sw[0] = 1'b1; | ||
- | end | ||
- | endmodule | ||
- | |||
- | </code> | ||
- | \\ | ||
- | |||